San Antonio, in Bexar County, is the tenth largest city in the U.S., with a population of 850,000 persons. It has a significant subculture (approx. 6,200 persons) of intravenous drug abusers (IVDAs) and a low prevalence (5%) of HIV infection. As of January 30, 1988, 183 AIDS cases were reported to the San Antonio Metropolitan Health District, of which 8.8% were IVDAs. This is considerably lower than the national average of 25% IVDAs in the total group of AIDS patients. This community provides an opportunity to demonstrate the effectiveness of different educational interventions in limiting the spread of HIV in IVDAs and other high-risk groups. The Substance Abuse Division, Department of Psychiatry, at the University of Texas Health Science Center at San Antonio will coordinate the project and the reserach and evaluation component. The San Antonio Metropolitan Health District will serve as the primary community outreach component. An estimated 1,250 subjects will be enrolled from four at-risk groups: 1) adult IVDAs, 2) sexual partners of IVDAs, 3) prostitues, and 4) adolescents IVDAs and runaways. Subjects will be recruited from treatment programs, the criminal justice system, shelters for runaways, housing projects, and other areas where these persons congregate. The initial assessment will include the AIDS Initial Assessment (AIA) Questionnaire, the Substance Abuse Problem Checklist, and HIV antibody testing. Subjects will be randomly assigned to a standard or intensive intervention. The standard intervention will include an AIDS fact sheet and a counseling session on risk-reduction techniques. The intensive intervention will incude an AIDS fact sheet, five weekly individualized counseling sessions, and partially subsidized treatment for IVDAs not enrolled in treatment. All subjects will be reinterviewed at 6 months and 12 months after enrollment. HIV antibody testing will be repeated at 12 months. Data analysis will assess the effectiveness of each intervention in regard to increasing AIDS knowledge, decreasing high-risk behaviors, and change of HIV antibody status over time.